Substrate structure and method for manufacturing a semiconductor package

ABSTRACT

A substrate structure includes a chip attach area and an upper side rail surrounding the chip attach area. The upper side rail includes an upper stress relief structure and an upper reinforcing structure. The upper stress relief structure surrounds the upper chip attach area. The upper reinforcing structure surrounds the upper stress relief structure. A stress relieving ability of the upper stress relief structure is greater than a stress relieving ability of the upper reinforcing structure. A structural strength of the upper reinforcing structure is greater than a structural strength of the upper stress relief structure.

BACKGROUND 1. Technical Field

The present disclosure generally relates to a substrate structure and a method for manufacturing a semiconductor package, and to a substrate structure having less warpage, and a method for manufacturing a semiconductor package by using the same.

2. Description of the Related Art

Design trends in the semiconductor industry include weight reduction and miniaturization of semiconductor products. However, techniques for weight reduction and miniaturization may result in manufacturing problems. For example, a thin semiconductor substrate is difficult to handle due a large warpage. As a result, a yield rate of the semiconductor products is low. Thus, reduction in warpage of the semiconductor substrate during the manufacturing process is an issue to be addressed.

SUMMARY

In accordance with an aspect of the present disclosure, a substrate structure includes a chip attach area and an upper side rail surrounding the chip attach area. The upper side rail includes an upper stress relief structure and an upper reinforcing structure. The upper stress relief structure surrounds the upper chip attach area. The upper reinforcing structure surrounds the upper stress relief structure. A stress relieving ability of the upper stress relief structure is greater than a stress relieving ability of the upper reinforcing structure. A structural strength of the upper reinforcing structure is greater than a structural strength of the upper stress relief structure.

In accordance with an aspect of the present disclosure, a substrate structure includes a first structure and a second structure. The first structure is disposed in a first region surrounding a chip attach area. A first occupancy ratio is defined as a ratio of an area of the first structure from a top view to an area of the entire first region from a top view. The second structure is disposed in a second region surrounding the first region. A second occupancy ratio is defined as a ratio of an area of the second structure from a top view to an area of the entire second region from a top view. The second occupancy ratio is different from the first occupancy ratio.

In accordance another aspect of the present disclosure, a method for manufacturing a semiconductor package includes: (a) providing a substrate structure, wherein the substrate structure includes a chip attach area and an upper side rail surrounding the chip attach area, the upper side rail includes an upper stress relief structure and an upper reinforcing structure, the upper stress relief structure surrounds the upper chip attach area, the upper reinforcing structure surrounds the upper stress relief structure, wherein a stress relieving ability of the upper stress relief structure is greater than a stress relieving ability of the upper reinforcing structure, and a structural strength of the upper reinforcing structure is greater than a structural strength of the upper stress relief structure; (b) attaching at least one semiconductor chip to the chip attach area; and (c) forming an encapsulant to cover the at least one semiconductor chip.

In accordance another aspect of the present disclosure, a method for manufacturing a semiconductor package includes: (a) providing a substrate structure, wherein the substrate structure includes a first structure and a second structure, the first structure is disposed in a first region surrounding a chip attach area, a first occupancy ratio is defined as a ratio of an area of the first structure from a top view to an area of the entire first region from a top view, the second structure is disposed in a second region surrounding the first region, a second occupancy ratio is defined as a ratio of an area of the second structure from a top view to an area of the entire second region from a top view, and the second occupancy ratio is different from the first occupancy ratio; (b) attaching at least one semiconductor chip to the chip attach area; and (c) forming an encapsulant to cover the at least one semiconductor chip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a top view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 2 illustrates an enlarged cross-sectional view taken along line 2-2 in a region “A” in FIG. 1.

FIG. 3 illustrates a top view of the substrate structure of FIG. 1, wherein an upper solder resist layer and a lower solder resist layer are omitted for clarity of illustration.

FIG. 4 illustrates an enlarged view of a region “B” in FIG. 3.

FIG. 5 illustrates an enlarged cross-sectional view taken along line 5-5 in FIG. 4.

FIG. 6 illustrates a bottom view of the substrate structure of FIG. 1, wherein a portion of a lower solder resist layer that covers the lower side rail is omitted for clarity of illustration.

FIG. 7 illustrates a top view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 8 illustrates an enlarged cross-sectional view taken along line 8-8 in a region “C” in FIG. 7.

FIG. 9 illustrates a top view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 10 illustrates a top view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 11 illustrates an enlarged cross-sectional view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 12 illustrates a bottom view of the substrate structure of FIG. 11.

FIG. 13 illustrates a bottom view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 14 illustrates a partially enlarged view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 15 illustrates a partially enlarged view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 16 illustrates a partially enlarged view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 17 illustrates a partially enlarged view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 18 illustrates a partially enlarged view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 19 illustrates a partially enlarged view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 20 illustrates a partially enlarged view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 21 illustrates a partially enlarged view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 22 illustrates a partially enlarged view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 23 illustrates a partially enlarged view of a substrate structure in accordance with some embodiments of the present disclosure.

FIG. 24 illustrates one or more stages of an example of a method for manufacturing a semiconductor package according to some embodiments of the present disclosure.

FIG. 25 illustrates one or more stages of an example of a method for manufacturing a semiconductor package according to some embodiments of the present disclosure.

FIG. 26 illustrates one or more stages of an example of a method for manufacturing a semiconductor package according to some embodiments of the present disclosure.

FIG. 27 illustrates one or more stages of an example of a method for manufacturing a semiconductor package according to some embodiments of the present disclosure.

FIG. 28 illustrates one or more stages of an example of a method for manufacturing a semiconductor package according to some embodiments of the present disclosure.

Common reference numerals are used throughout the drawings and the detailed description to indicate the same or similar components. The present disclosure can be best understood from the following detailed description taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION

The following disclosure provides for many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below. These are, of course, merely examples and are not intended to be limiting. In the present disclosure, reference to the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. Besides, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Embodiments of the present disclosure are discussed in detail below. It should be appreciated, however, that the present disclosure provides many applicable concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative and do not limit the scope of the disclosure.

FIG. 1 illustrates a top view of a substrate structure 1 in accordance with some embodiments of the present disclosure. FIG. 2 illustrates an enlarged cross-sectional view taken along line 2-2 in a region “A” in FIG. 1. The substrate structure 1 includes main body 10, a chip attach area 2, an upper side rail 3, an upper metal layer 16, a bottom layout area 2 a, a lower side rail 6, a lower metal layer 17, an upper solder resist layer 13, a lower solder resist layer 15, a plurality of conductive vias 18 and a plurality of position holes 103. As shown in FIG. 1, the substrate structure 1 may be a strip type substrate; however, in other embodiments, the substrate structure 1 may be a panel type substrate.

The material of the main body 10 may be a dielectric material, which may include a glass reinforced epoxy material (such as FR4), bismaleimide triazine (BT), epoxy resin, silicon, printed circuit board (PCB) material, glass, ceramic or photoimageable dielectric (PID) material. The main body 10 has an upper surface 101 and a lower surface 102 opposite to the upper surface 101. The upper surface 101 of the main body 10 includes the chip attach area 2 and the upper side rail 3 surrounding the chip attach area 2. The upper side rail 3 may include a first region 31 surrounding the chip attach area 2, and a second region 32 surrounding the first region 31. There may be a second boundary line 30 between the second region 32 and the first region 31. In one embodiment, the second boundary line 30 may be an imaginary cutting line. It is to be noted that in some embodiments, the second boundary line 30 may be a solid line, that is, it may be an actual boundary.

The upper metal layer 16 is disposed adjacent to the upper surface 101 of the main body 10, and is a patterned metal layer that includes an upper circuit layer 12 disposed in the chip attach area 2, a first structure 4 (e.g., an upper stress relief structure) disposed in the first region 31, and a second structure 5 (e.g., an upper reinforcing structure) disposed in the second region 32. In some embodiments, the upper circuit layer 12, the first structure 4 (e.g., the upper stress relief structure) and the second structure 5 (e.g., the upper reinforcing structure) are disposed at the same layer, and are formed concurrently at a process stage. A material of the upper metal layer 16 (including the upper circuit layer 12, the first structure 4 (e.g., an upper stress relief structure) and the second structure 5 (e.g., an upper reinforcing structure)) may include a metal material such as copper, gold, aluminum, or other suitable metal. In one embodiment, the upper metal layer 16 may be the topmost metal layer, and there may be one or more metal layers disposed under the upper metal layer 16 and embedded in the main body 10.

The lower surface 102 of the main body 10 includes the bottom layout area 2 a and the lower side rail 6 surrounding the bottom layout area 2 a. The lower side rail 6 may include a third region 61 surrounding the bottom layout area 2 a, and a fourth region 62 surrounding the third region 61. The lower metal layer 17 is disposed adjacent to the lower surface 102 of the main body 10, and is a patterned metal layer that includes a lower circuit layer 14 disposed in the bottom layout area 2 a, a third structure 7 (e.g., a lower stress relief structure) disposed in the third region 61, and a fourth structure 8 (e.g., a lower reinforcing structure) disposed in the fourth region 62. In some embodiments, the lower circuit layer 14, the third structure 7 (e.g., a lower stress relief structure) and the fourth structure 8 (e.g., a lower reinforcing structure) are disposed at the same layer, and are formed concurrently at a process stage. A material of the lower metal layer 17 (including the lower circuit layer 14, the third structure 7 (e.g., a lower stress relief structure) and the fourth structure 8 (e.g., a lower reinforcing structure)) may include a metal material such as copper, gold, aluminum, or other suitable metal. In one embodiment, the lower metal layer 17 may be the bottommost metal layer, and there may be one or more metal layers disposed above the lower metal layer 17 and embedded in the main body 10.

The conductive vias 18 may extend through the main body 10. Thus, the upper circuit layer 12 is electrically connected to the lower circuit layer 14 through the conductive vias 18.

The chip attach area 2 is used for at least one semiconductor chip 92 (FIG. 24) to be disposed thereon. As shown in FIG. 1, the chip attach area 2 includes a plurality of unit areas 21. For example, 2*8=16 unit areas 21. Each of the unit areas 21 is defined by a plurality of first boundary lines 20 cross with each other, and is a place wherein at least one semiconductor chip 92 (FIG. 24) is disposed on. In one embodiment, the first boundary lines 20 may be an imaginary cutting line. It is to be noted that in some embodiments, the first boundary lines 20 may be solid lines, that is, they may be actual boundaries. In addition, after a subsequent molding process, a dicing process (or singulation process) may be performed along the first boundary lines 20, so that each of the unit areas 21 remains in each final product (e.g., the semiconductor package 9 (FIG. 28)).

The upper solder resist layer 13 is disposed on the upper surface 101 of the main body 10 to cover at least a portion of the upper metal layer 16. The lower solder resist layer 15 is disposed on the lower surface 102 of the main body 10 to cover at least a portion of the lower metal layer 17. The position holes 103 extend through the substrate structure 1 and are used for position pins to be inserted therein. Thus, the position of the substrate structure 1 is ensured during the subsequent manufacturing process.

FIG. 3 illustrates a top view of the substrate structure 1 of FIG. 1, wherein the upper solder resist layer 13 and the lower solder resist layer 15 are omitted for clarity of illustration. As shown in FIG. 3, the upper circuit layer 12 may be disposed in each of the unit areas 21, the first structure 4 (e.g., the upper stress relief structure) may be disposed in the first region 31, and the second structure 5 (e.g., the upper reinforcing structure) may be disposed in the second region 32. Thus, the first structure 4 (e.g., the upper stress relief structure) surrounds the chip attach area 2, and the second structure 5 (e.g., the upper reinforcing structure) surrounds the first structure 4 (e.g., the upper stress relief structure). The first structure 4 (e.g., the upper stress relief structure) is disposed between the chip attach area 2 and the second structure 5 (e.g., the upper reinforcing structure).

FIG. 4 illustrates an enlarged view of a region “B” in FIG. 3. FIG. 5 illustrates an enlarged cross-sectional view taken along line 5-5 in FIG. 4. The upper circuit layer 12 may include a plurality of conductive traces 121, a plurality of conductive pads 122, and a plurality of conductive fingers 123. In some embodiments, the layouts of the upper circuit layers 12 in all of the unit areas 21 may be same with each other. In an embodiment, the conductive finger 123 may have an upper surface finish layer 191, such as an electroplated gold layer or a tin plating layer. It is understood that the upper surface finish layer 191 may be omitted. A material of the upper circuit layer 12 (including the upper stress relief structure includes a metal material, and a material of the upper reinforcing structure includes a metal material. Similarly, the lower circuit layer 14 may include a plurality of conductive traces 141, a plurality of conductive pads 142, and a plurality of external connectors 143 (e.g., ball pads). In an embodiment, the external connector 143 may have a lower surface finish layer 192, such as an electroplated gold layer or a tin plating layer. A material of the lower circuit layer 14 may be same as the material of the upper circuit layer 12.

The first structure 4 (e.g., the upper stress relief structure) may be physically connected to the second structure 5 (e.g., the upper reinforcing structure). Alternatively, the first structure 4 (e.g., the upper stress relief structure) may be physically separated from the second structure 5 (e.g., the upper reinforcing structure). The first structure 4 (e.g., the upper stress relief structure) and the second structure 5 (e.g., the upper reinforcing structure) may have different functions. For example, the first structure 4 (e.g., the upper stress relief structure) may be used for releasing the stress of the substrate structure 1 so as to reduce the residual stress in the substrate structure 1. That is, a stress relieving ability of the first structure 4 (e.g., the upper stress relief structure) is greater than a stress relieving ability of the second structure 5 (e.g., the upper reinforcing structure). Further, the second structure 5 (e.g., the upper reinforcing structure) may be used for providing rigidity and stiffness so as to resist a deformation of the substrate structure 1. That is, a structural strength of the second structure 5 (e.g., the upper reinforcing structure) is greater than a structural strength of the first structure 4 (e.g., the upper stress relief structure). The above-mentioned two functions may reduce the warpage of the substrate structure 1 during the manufacturing process.

A pattern of the first structure 4 (e.g., the upper stress relief structure) may be the same as or different from a pattern of the second structure 5 (e.g., the upper reinforcing structure). As shown in FIG. 4, the pattern of the first structure 4 (e.g., the upper stress relief structure) is in a net shape from a top view. In one embodiment, the first structure 4 (e.g., the upper stress relief structure) includes a plurality of strips 40 cross with each other to form the net shape. A width W₄ of each of the strips 40 may be about 0.1 millimeter (mm) to about 0.7 mm. A gap G between two adjacent strips 40 may be about 0.4 mm to about 2.0 mm. Since the pattern of the first structure 4 (e.g., the upper stress relief structure) may be in a grid shape, and the strips 40 are not parallel with an edge 11 of the substrate structure 1, most of the stress in the substrate structure 1 may be released through the first structure 4 (e.g., the upper stress relief structure) readily. As shown in FIG. 4, the strips 40 define a plurality of empty holes 43 arranged along two directions (e.g., a first direction 41 and a second direction 42). The two directions (e.g., a first direction 41 and a second direction 42) are neither perpendicular to nor parallel with the edge 11 of the substrate structure 1. Thus, the two directions (e.g., a first direction 41 and a second direction 42) are stress relief directions of the first structure 4 (e.g., the upper stress relief structure). The first structure 4 (e.g., the upper stress relief structure) may have at least two stress relief directions.

The second structure 5 (e.g., the upper reinforcing structure) may include at least one row of segments 50 substantially parallel with the edge 11 of the substrate structure 1. As shown in FIG. 4, the second structure 5 (e.g., the upper reinforcing structure) may include three parallel rows of the segments 50 such as an innermost row 51 of first segments 511, an outermost row 52 of second segments 521 and an intermediate row 53 of third segments 531. The shape of each of the segments 50 (e.g., the first segments 511, the second segments 521 and the third segments 531) may be rectangular or square. A size of each of the first segments 511 is substantially equal to a size of each of the second segments 521, and a size of each of the third segments 531 is different from the size of each of the first segments 511. For example, a width W₁ of the first segment 511 may be equal to a width W₂ of the second segments 521, which may be about 1 mm to about 2 mm. A width W₃ of the third segment 531 may be equal to the width W₂ of the second segments 521, which may be about 1 mm to about 2 mm. It is noted that the width of the segments 50 (e.g., the width W₁ of the first segment 511, the width W₂ of the second segments 521 and the width W₃ of the third segment 531) is greater than a gap between the innermost row 51 and the intermediate row 53, or a gap between the outermost row 52 and the intermediate row 53 of third segments 531. Further, a length of the first segment 511 may be equal to a length L₂ of the second segments 521, which may be about 2 mm to 4 mm. A length L₃ of the third segment 531 may be about 1 mm to about 2 mm, which may be less than the length L₂ of the second segments 521.

In addition, the first segments 511 are aligned with the second segments 521, and the third segments 531 are misaligned with the first segments 511 and the second segments 521. For example, two adjacent first segments 511 define a first gap 512, two adjacent second segments 521 define a second gap 522, and a center of the third segment 531 is disposed between the first gap 521 and the second gap 522. In one embodiment, the first gap 512 may be equal to the second gap 522, which may be about 0.1 mm to 0.7 mm.

Since a width of the segments 50 (e.g., the width W₁ of the first segment 511, the width W₂ of the second segments 521 and the width W₃ of the third segment 531) is greater than the width W₄ of each of the strips 40, and the segments 50 (e.g., the first segment 511, the second segments 521 and the third segment 531) are arranged in parallel with the edge 11 of the substrate structure 1, the second structure 5 (e.g., the upper reinforcing structure) may be a rigid and stiff structure.

As shown in FIG. 3 and FIG. 4, a first occupancy ratio is defined as a ratio of an area of a solid portion of the first structure 4 (e.g., the upper stress relief structure) from a top view to an area of the entire first region 31 from a top view. A second occupancy ratio is defined as a ratio of an area of a solid portion of the second structure 5 (e.g., the upper reinforcing structure) from a top view to an area of the entire second region 32 from a top view. The second occupancy ratio may be different from the first occupancy ratio. For example, the second occupancy ratio may be greater than the first occupancy ratio. In one embodiment, the first structure 4 (e.g., the upper stress relief structure) includes copper; thus, the first occupancy ratio is a first residual copper ratio. Similarly, the second structure 5 (e.g., the upper reinforcing structure) includes copper; thus, the second occupancy ratio is a second residual copper ratio. Therefore, the second residual copper ratio of the second structure 5 (e.g., the upper reinforcing structure) is greater than the first residual copper ratio of the first structure 4 (e.g., the upper stress relief structure).

FIG. 6 illustrates a bottom view of the substrate structure 1 of FIG. 1, wherein a portion of the lower solder resist layer 15 that covers the lower side rail 6 is omitted for clarity of illustration. The bottom layout area 2 a corresponds to the chip attach area 2 of FIG. 3. As shown in FIG. 6, the bottom layout area 2 a includes a plurality of unit areas 21 a. Each of the unit areas 21 a corresponds to each of the unit areas 21, and is also defined by the first boundary lines 20.

As shown in FIG. 2, FIG. 3 and FIG. 6, the third structure 7 (e.g., a lower stress relief structure) may correspond to the first structure 4 (e.g., the upper stress relief structure). A pattern of the third structure 7 (e.g., a lower stress relief structure) may be the same as the pattern of the first structure 4 (e.g., the upper stress relief structure). That is, the pattern of the third structure 7 (e.g., a lower stress relief structure) may include a plurality of strips 70 cross with each other to form a net shape.

The fourth structure 8 (e.g., a lower reinforcing structure) may corresponds to the second structure 5 (e.g., the upper reinforcing structure). A pattern of the fourth structure 8 (e.g., a lower reinforcing structure) may the same as the pattern of the second structure 5 (e.g., the upper reinforcing structure). That is, the fourth structure 8 (e.g., a lower reinforcing structure) may include at least one row of segments 80 substantially parallel with the edge 11 of the substrate structure 1. As shown in FIG. 2, the fourth structure 8 (e.g., a lower reinforcing structure) may include three parallel rows of the segments 80 such as an innermost row of first segments 811, an outermost row of second segments 821 and an intermediate row of third segments 831. The size and shape of each of the segments 80 (e.g., the first segments 811, the second segments 821 and the third segments 831) may be substantially equal to the size and shape of each of the segments 50 (e.g., the first segments 511, the second segments 521 and the third segments 531)

The third structure 7 (e.g., a lower stress relief structure) and the fourth structure 8 (e.g., a lower reinforcing structure) may have different functions. For example, the third structure 7 (e.g., a lower stress relief structure) may be used for releasing the stress of the substrate structure 1. That is, a stress relieving ability of the third structure 7 (e.g., a lower stress relief structure) is greater than a stress relieving ability of the fourth structure 8 (e.g., a lower reinforcing structure). Further, the fourth structure 8 (e.g., a lower reinforcing structure) may be used for providing rigidity and stiffness. That is, a structural strength of the fourth structure 8 (e.g., a lower reinforcing structure) is greater than a structural strength of the third structure 7 (e.g., a lower stress relief structure).

As shown in FIG. 5 and FIG. 6, a third occupancy ratio is defined as a ratio of an area of a solid portion of the third structure 7 (e.g., the lower stress relief structure) from a bottom view to an area of the entire third region 61 from a bottom view. A fourth occupancy ratio is defined as a ratio of an area of a solid portion of the fourth structure 8 (e.g., the lower reinforcing structure) from a bottom view to an area of the entire fourth region 62 from a bottom view. The fourth occupancy ratio may be different from the third occupancy ratio. For example, the fourth occupancy ratio may be greater than the third occupancy ratio. In one embodiment, the third structure 7 (e.g., the lower stress relief structure) includes copper; thus, the third occupancy ratio is a residual copper ratio. Similarly, the fourth structure 8 (e.g., the lower reinforcing structure) includes copper; thus, the fourth occupancy ratio is a residual copper ratio. Therefore, the residual copper ratio of the fourth structure 8 (e.g., the lower reinforcing structure) is greater than the residual copper ratio of the third structure 7 (e.g., the lower stress relief structure).

As shown in FIG. 5 and FIG. 6, a size of the lower side rail 6 is substantially equal to a size of the upper side rail 3. The sizes of the third region 61 and the fourth region 62 are substantially equal to the sizes of the first region 31 and the second region 32, respectively. Thus, a size of the third structure 7 (e.g., a lower stress relief structure) of the lower side rail 6 is substantially equal to a size of the first structure 4 (e.g., the upper stress relief structure) of the upper side rail 3, and a size of the fourth structure 8 (e.g., a lower reinforcing structure) of the lower side rail 6 is substantially equal to a size of the second structure 5 (e.g., the upper reinforcing structure) of the upper side rail 3. However, in other embodiment, the size of the lower side rail 6 may be different from the size of the upper side rail 3. The sizes of the third region 61 and the fourth region 62 may be different from the sizes of the first region 31 and the second region 32, respectively. Thus, the size of the third structure 7 (e.g., a lower stress relief structure) of the lower side rail 6 may be different from the size of the first structure 4 (e.g., the upper stress relief structure) of the upper side rail 3, and the size of the fourth structure 8 (e.g., a lower reinforcing structure) of the lower side rail 6 may be different from the size of the second structure 5 (e.g., the upper reinforcing structure) of the upper side rail 3.

In the embodiment illustrated in FIG. 1 to FIG. 6, an upper residual metal ratio is defined as a ratio of an area of the upper metal layer 16 (including the upper circuit layer 12, the first structure 4 (e.g., the upper stress relief structure) and the second structure 5 (e.g., the upper reinforcing structure)) form a top view to an area of the entire upper surface 101 of the main body 10. Since the upper metal layer 16 may include copper; thus, the upper residual metal ratio is an upper residual copper ratio. It is noted that the upper residual metal ratio (e.g., the upper residual copper ratio) may be adjusted by adjusting the first occupancy ratio (the first residual copper ratio) of the first structure 4 (e.g., the upper stress relief structure) and the second occupancy ratio (the second residual copper ratio of the second structure 5. Similarly, a lower residual metal ratio is defined as a ratio of an area of the lower metal layer 17 (including the lower circuit layer 14, the third structure 7 (e.g., the lower stress relief structure) and the fourth structure 8 (e.g., the lower reinforcing structure)) form a bottom view to an area of the entire lower surface 102 of the main body 10. Since the lower metal layer 17 may include copper; thus, the lower residual metal ratio is a lower residual copper ratio. It is noted that the lower residual metal ratio (e.g., the lower residual copper ratio) may be adjusted by adjusting the third occupancy ratio (the third residual copper ratio) of the third structure 7 (e.g., the lower stress relief structure) and the fourth occupancy ratio (the fourth residual copper ratio of the fourth structure 8. Therefore, a difference between the upper residual metal ratio and the lower residual metal ratio may be adjusted to be less than or equal to about 4%, about 3%, about 2%, about 1%, or about 0. As a result, a warpage of the substrate structure 1 is reduced.

In addition, an upper solder resist cover ratio is defined as a ratio of an area of the upper solder resist layer 13 from a top view to an area of the entire upper surface 101 of the main body 10. The upper solder resist cover ratio is adjustable. Similarly, a lower solder resist cover ratio is defined as a ratio of an area of the lower solder resist layer 15 from a bottom view to an area of the entire lower surface 102 of the main body 10. The lower solder resist cover ratio is adjustable. Thus, a difference between the upper solder resist cover ratio and the lower solder resist cover ratio may be adjusted to be less than or equal to about 5%, about 4%, about 3%, about 2%, about 1%, or about 0. As a result, a warpage of the substrate structure 1 is further reduced.

FIG. 7 illustrates a top view of a substrate structure 1 a in accordance with some embodiments of the present disclosure. FIG. 8 illustrates an enlarged cross-sectional view taken along line 8-8 in a region “C” in FIG. 7. The substrate structure 1 a is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for structures of the upper solder resist layer 13 and the lower solder resist layer 15. As shown in FIG. 7 and FIG. 8, the upper solder resist layer 13 covers the upper circuit layer 12 and the second structure 5 (e.g., the upper reinforcing structure), but does not cover the first structure 4 (e.g., the upper stress relief structure). That is, the upper solder resist layer 13 uncovers the first structure 4 (e.g., the upper stress relief structure). Similarly, the lower solder resist layer 15 covers the lower circuit layer 14 and the fourth structure 8 (e.g., the lower reinforcing structure), but does not cover the third structure 7 (e.g., the lower stress relief structure). That is, the lower solder resist layer 15 uncovers the third structure 7 (e.g., the lower stress relief structure).

FIG. 9 illustrates a top view of a substrate structure 1 b in accordance with some embodiments of the present disclosure. The substrate structure 1 b is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for structures of the upper solder resist layer 13 and the lower solder resist layer 15. As shown in FIG. 9, the upper solder resist layer 13 covers the upper circuit layer 12, but does not cover the first structure 4 (e.g., the upper stress relief structure) and the second structure 5 (e.g., the upper reinforcing structure). That is, the upper solder resist layer 13 uncovers the first structure 4 (e.g., the upper stress relief structure) and the second structure 5 (e.g., the upper reinforcing structure). Similarly, the lower solder resist layer 15 covers the lower circuit layer 14, but does not cover the third structure 7 (e.g., the lower stress relief structure) and the fourth structure 8 (e.g., the lower reinforcing structure). That is, the lower solder resist layer 15 uncovers the third structure 7 (e.g., the lower stress relief structure) and the fourth structure 8 (e.g., the lower reinforcing structure).

FIG. 10 illustrates a top view of a substrate structure 1 c in accordance with some embodiments of the present disclosure. The substrate structure 1 c is similar to the substrate structure 1 b in FIG. 9 except for a structure of the second structure 5 c (e.g., the upper reinforcing structure). As shown in FIG. 10, the pattern of the second structure 5 c (e.g., the upper reinforcing structure) is in a continuous ring shape from a top view. That is, the second region 32 of the upper side rail 3 is full of a metal material. The shape and size of the second structure 5 c (e.g., the upper reinforcing structure) are conformal with the shape and size of the second region 32 of the upper side rail 3. Further, the first structure 4 (e.g., the upper stress relief structure) is physically connected to the second structure 5 c (e.g., the upper reinforcing structure).

FIG. 11 illustrates an enlarged cross-sectional view of a substrate structure 1 d in accordance with some embodiments of the present disclosure. FIG. 12 illustrates a bottom view of the substrate structure 1 d of FIG. 11. The substrate structure 1 d is similar to the substrate structure 1 c in FIG. 10 except for structures of the lower side rail 6 d, the third structure 7 d (e.g., the lower stress relief structure) and the fourth structure 8 d (e.g., the lower reinforcing structure). The lower side rail 6 d includes a third region 61 d surrounding the bottom layout area 2 a, and a fourth region 62 d surrounding the third region 61 d. A width of the third region 61 d is greater than a width of the first region 31, and a width of the fourth region 62 d is less than a width of the second region 32. That is, the second boundary 30′ on the lower surface 102 of the main body 10 is not aligned with the second boundary 30 on the upper surface 101 of the main body 10.

As shown in FIG. 12, the third structure 7 d (e.g., the lower stress relief structure) is disposed on the entire third region 61 d, and includes the strips 70 cross with each other. In addition, the pattern of the fourth structure 8 d (e.g., the lower reinforcing structure) is in a continuous ring shape from a bottom view. That is, the fourth region 62 d of the lower side rail 6 d is full of a metal material. Thus, a size (e.g., a width) of the fourth structure 8 d (e.g., the lower reinforcing structure) is less than a size (e.g., a width) of the second structure 5 c (e.g., the upper reinforcing structure).

FIG. 13 illustrates a bottom view of a substrate structure 1 e in accordance with some embodiments of the present disclosure. The substrate structure 1 e is similar to the substrate structure 1 d in FIG. 11 and FIG. 12 except for a structure of the fourth structure 8 e (e.g., the lower reinforcing structure). As shown in FIG. 13, the fourth structure 8 e (e.g., the lower reinforcing structure) is in a discontinuous ring shape from a bottom view. Thus, the fourth structure 8 e (e.g., the lower reinforcing structure) includes a row of segments 80 e.

FIG. 14 illustrates a partially enlarged view of a substrate structure if in accordance with some embodiments of the present disclosure. The substrate structure if is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for a shape of the third segment 531 f in the intermediate row 53 f of the second structure 5 f (e.g., the upper reinforcing structure). As shown in FIG. 14, the third segment 531 f is in a diamond shape.

FIG. 15 illustrates a partially enlarged view of a substrate structure 1 g in accordance with some embodiments of the present disclosure. The substrate structure 1 g is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for a shape of the third segment 531 g in the intermediate row 536 g of the second structure 5 g (e.g., the upper reinforcing structure). As shown in FIG. 15, the third segment 531 g is in a star shape.

FIG. 16 illustrates a partially enlarged view of a substrate structure 1 h in accordance with some embodiments of the present disclosure. The substrate structure 1 h is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for a shape of the third segment 531 h in the intermediate row 53 h of the second structure 5 h (e.g., the upper reinforcing structure). As shown in FIG. 16, the third segment 531 h is in a hexagon shape.

FIG. 17 illustrates a partially enlarged view of a substrate structure 1 i in accordance with some embodiments of the present disclosure. The substrate structure 1 i is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for a shape of the third segment 531 i in the intermediate row 53 i of the second structure 5 i (e.g., the upper reinforcing structure). As shown in FIG. 17, the third segment 531 i is in a cross shape.

FIG. 18 illustrates a partially enlarged view of a substrate structure 1 j in accordance with some embodiments of the present disclosure. The substrate structure 1 j is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for a structure of the second structure 5 j (e.g., the upper reinforcing structure). As shown in FIG. 18, the second structure 5 j (e.g., the upper reinforcing structure) includes one row of segments 50 j. The segments 50 j are parallel with one another, so as to form a zebra stripe pattern. In one embodiment, a length L₅ of the segment 50 j is about 2 mm to about 6 mm, a width W₅ of the segment 50 j is about 1 mm to about 2 mm, and a gap g₅ between two adjacent segments 50 j is about 0.1 mm to about 0.7 mm.

FIG. 19 illustrates a partially enlarged view of a substrate structure 1 k in accordance with some embodiments of the present disclosure. The substrate structure 1 k is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for a structure of the second structure 5 k (e.g., the upper reinforcing structure). As shown in FIG. 19, the second structure 5 k (e.g., the upper reinforcing structure) includes one row of segments 50 k. Each of the segments 50 k defines two openings 54. In one embodiment, a length L₇ of the segment 50 k is about 4 mm to about 8 mm, a width W₇ of the segment 50 k is about 2 mm to about 6 mm, and a length L₈ of the opening 54 is about 2 mm to about 6 mm.

FIG. 20 illustrates a partially enlarged view of a substrate structure 1 m in accordance with some embodiments of the present disclosure. The substrate structure 1 m is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for a structure of the second structure 5 m (e.g., the upper reinforcing structure). As shown in FIG. 20, the second structure 5 m (e.g., the upper reinforcing structure) includes one row of segments 50 m. Each of the segments 50 m is in an “H” shape. In one embodiment, a length L₉ of the segment 50 m is about 4 mm to about 8 mm.

FIG. 21 illustrates a partially enlarged view of a substrate structure 1 n in accordance with some embodiments of the present disclosure. The substrate structure 1 n is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for a structure of the second structure 5 n (e.g., the upper reinforcing structure). As shown in FIG. 21, the second structure 5 n (e.g., the upper reinforcing structure) includes one row of segments 50 n. Each of the segments 50 n is a combination of four bars 55. Two bars 55 across with each other to form a “X” shape, and the other two bars 55 are disposed on a top portion and a bottom portion of the “X” shape respectively. In one embodiment, a length L₁₀ of the segment 50 n is about 4 mm to about 8 mm, and a width of each of the bars 55 is about 1 mm to about 2 mm.

FIG. 22 illustrates a partially enlarged view of a substrate structure 1 p in accordance with some embodiments of the present disclosure. The substrate structure 1 p is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for structures of the upper side rail 3 p, the first structure 4 p (e.g., the upper stress relief structure) and the second structure 5 p (e.g., the upper reinforcing structure). The upper side rail 3 p includes a first region 31 p and a second region 32 p surrounding the first region 31 p. A width of the second region 32 p is greater than a width of the first region 31 p. The first structure 4 p (e.g., the upper stress relief structure) may include three parallel rows of segments such as an innermost row 41 p of first segments 411 p, an outermost row 42 p of second segments 421 p and an intermediate row 43 p of third segments 431 p. Further, the second structure 5 p (e.g., the upper reinforcing structure) may include three parallel rows of segments such as an innermost row 51 p of first segments 511 p, an outermost row 52 p of second segments 521 p and an intermediate row 53 p of third segments 531 p. Thus, a pattern of the first structure 4 p (e.g., the upper stress relief structure) is substantially same as a pattern of the second structure 5 p (e.g., the upper reinforcing structure). A width W₁₁ of the first segments 511 p of the second structure 5 p is greater than a width W₁₂ of the second segments 421 p of the first structure 4 p. For example, the width W₁₁ of the first segments 511 p of the second structure 5 p may be greater than 1.3 times, 1.5 times, or 2 times the width W₁₂ of the second segments 421 p of the first structure 4 p.

FIG. 23 illustrates a partially enlarged view of a substrate structure 1 q in accordance with some embodiments of the present disclosure. The substrate structure 1 q is similar to the substrate structure 1 in FIG. 1 to FIG. 6 except for a structures of the second structure 5 q (e.g., the upper reinforcing structure). As shown in FIG. 23, the second structure 5 q (e.g., the upper reinforcing structure) includes a plurality of strips 50 q cross with each other to form a net shape. Thus, a pattern of the first structure 4 (e.g., the upper stress relief structure) is substantially same as a pattern of the second structure 5 q (e.g., the upper reinforcing structure). A width W₁₃ of each of the strips 50 q may be greater than the width W₄ of each of the strips 40, and a gap G′ between two adjacent strips 50 q may be greater than the gap G between two adjacent strips 40.

FIG. 24 through FIG. 28 illustrate a method for manufacturing a semiconductor package according to some embodiments of the present disclosure.

Referring to FIG. 24, a substrate structure 1 is provided. The substrate structure 1 is substantially same as the substrate structure 1 shown in FIG. 1 to FIG. 6. The substrate structure 1 includes a chip attach area 2 and an upper side rail 3 surrounding the chip attach area 2. The upper side rail 3 includes a first structure 4 (e.g., an upper stress relief structure) and a second structure 5 (e.g., an upper reinforcing structure). The first structure 4 (e.g., an upper stress relief structure) surrounds the chip attach area 2, and the second structure 5 (e.g., an upper reinforcing structure) surrounds the first structure 4 (e.g., an upper stress relief structure). A stress relieving ability of the first structure 4 (e.g., an upper stress relief structure) is greater than a stress relieving ability of the second structure 5 (e.g., an upper reinforcing structure). A structural strength of the second structure 5 (e.g., an upper reinforcing structure) is greater than a structural strength of the first structure 4 (e.g., an upper stress relief structure). In some embodiments, the substrate structure 1 may be replace by the substrate structures 1 a, 1 b, 1 c, 1 d, 1 e, 1 f, 1 g, 1 h, 1 i, 1 j, 1 k, 1 m, 1 n, 1 p of FIG. 7 to FIG. 23.

Then, at least one semiconductor chip 92 is attached to the chip attach area 2. As shown in FIG. 24, the semiconductor chip 29 is electrically connected to the substrate structure 1 by wire bonding. That is, a backside of the semiconductor chip 29 is adhered to the upper solder resist layer 13 on the upper surface 101 of the main body 10, and an active surface of the semiconductor chip 29 is electrically connected to the upper surface finish layer 191 on the conductive fingers 123 of the upper circuit layer 12 through a plurality of bonding wires 94. In other embodiments, the semiconductor chip 29 may be electrically connected to the substrate structure 1 by flip-chip bonding.

Referring to FIG. 25, a molding mold 90 is provided. The molding mold 90 has a bottom surface 901 and an inner lateral surface 903. The inner lateral surface 903 defines a mold cavity 902. The inner lateral surface 903 may be aligned with the first boundary line 20. Alternatively, the inner lateral surface 903 may be aligned with a position within the first region 31.

Referring to FIG. 26, the bottom surface 901 of the molding mold 90 is pressed against the upper side rail 3 of the substrate structure 1. Thus, the chip attach area 2, the semiconductor chip 29 and the bonding wires 94 are accommodated in the mold cavity 902. In other words, the first structure 4 (e.g., an upper stress relief structure), the second structure 5 (e.g., an upper reinforcing structure) and the first solder resist layer 13 on the first structure 4 and the second structure 5 are tightly pressed by the bottom surface 901 of the molding mold 90, so that the mold cavity 902 forms an enclosed space. In some embodiments that the first solder resist layer 13 does not cover the first structure 4 and/or the second structure 5, the bottom surface 901 of the molding mold 90 may press the first structure 4 and/or the second structure 5 directly.

Referring to FIG. 27, an encapsulant 96 (e.g., a molding compound) is formed or filled in the mold cavity 902 to cover the chip attach area 2, the semiconductor chip 29 and the bonding wires 94. During the molding process, the pattern of the first structure 4 (e.g., an upper stress relief structure) may prevent the encapsulant 96 4) from overflowing. Then, the encapsulant 96 is cured. Then, the molding mold 90 is removed.

Referring to FIG. 28, a singulation process is conducted along the first boundary line 20 so as to form a plurality of semiconductor packages 9. Each of the semiconductor packages 9 includes each of the unit areas 21. In addition, the upper side rail 3 (and the lower side rail 6) is disregarded.

As used herein, the terms “substantially,” “substantial,” “approximately,” and “about” are used to denote and account for small variations. For example, when used in conjunction with a numerical value, the terms can refer to a range of variation of less than or equal to ±10% of that numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. As another example, a thickness of a film or a layer being “substantially uniform” can refer to a standard deviation of less than or equal to ±10% of an average thickness of the film or the layer, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. The term “substantially coplanar” can refer to two surfaces within 50 μm of lying along a same plane, such as within 40 μm within 30 μm within 20 μm within 10 μm or within 1 μm of lying along the same plane. Two components can be deemed to be “substantially aligned” if, for example, the two components overlap or are within 200 μm within 150 μm within 100 μm within 50 μm within 40 μm within 30 μm within 20 μm within 10 μm or within 1 μm of overlapping. Two surfaces or components can be deemed to be “substantially perpendicular” if an angle therebetween is, for example, 90°±10°, such as ±5°, ±4°, ±3°, ±2°, ±1°, ±0.5°, ±0.1°, or ±0.05°. When used in conjunction with and event or circumstance, the terms “substantially,” “substantial,” “approximately,” and “about” can refer to instances in which the event or circumstance occurs precisely, as well as instances in which the event or circumstance occurs to a close approximation.

In the description of some embodiments, a component provided “on” another component can encompass cases where the former component is directly on (e.g., in physical contact with) the latter component, as well as cases where one or more intervening components are located between the former component and the latter component.

Additionally, amounts, ratios, and other numerical values are sometimes presented herein in a range format. It can be understood that such range formats are used for convenience and brevity, and should be understood flexibly to include not only numerical values explicitly specified as limits of a range, but also all individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly specified.

While the present disclosure has been described and illustrated with reference to specific embodiments thereof, these descriptions and illustrations do not limit the present disclosure. It can be clearly understood by those skilled in the art that various changes may be made, and equivalent elements may be substituted within the embodiments without departing from the true spirit and scope of the present disclosure as defined by the appended claims. The illustrations may not necessarily be drawn to scale. There may be distinctions between the artistic renditions in the present disclosure and the actual apparatus, due to variables in manufacturing processes and such. There may be other embodiments of the present disclosure which are not specifically illustrated. The specification and drawings are to be regarded as illustrative rather than restrictive. Modifications may be made to adapt a particular situation, material, composition of matter, method, or process to the objective, spirit and scope of the present disclosure. All such modifications are intended to be within the scope of the claims appended hereto. While the methods disclosed herein have been described with reference to particular operations performed in a particular order, it can be understood that these operations may be combined, sub-divided, or re-ordered to form an equivalent method without departing from the teachings of the present disclosure. Therefore, unless specifically indicated herein, the order and grouping of the operations are not limitations of the present disclosure. 

What is claimed is:
 1. A method for manufacturing a semiconductor package, comprising: (a) providing a substrate structure, wherein the substrate structure includes a chip attach area and an upper side rail surrounding the chip attach area, the upper side rail includes an upper stress relief structure and an upper reinforcing structure, the upper stress relief structure surrounds the upper chip attach area, the upper reinforcing structure surrounds the upper stress relief structure, wherein a stress relieving ability of the upper stress relief structure is greater than a stress relieving ability of the upper reinforcing structure, and a structural strength of the upper reinforcing structure is greater than a structural strength of the upper stress relief structure, wherein the upper stress relief structure includes copper, the upper reinforcing structure includes copper, and a residual copper ratio of the upper reinforcing structure is greater than a residual copper ratio of the upper stress relief structure; (b) attaching at least one semiconductor chip to the chip attach area; and (c) forming an encapsulant to cover the at least one semiconductor chip.
 2. The method of claim 1, wherein in (a), the upper stress relief structure includes a plurality of strips cross with each other to form a net shape.
 3. The method of claim 1, wherein in (a), a pattern of the upper reinforcing structure is in a continuous ring shape from a top view.
 4. The method of claim 1, wherein in (a), the upper reinforcing structure includes at least one row of segments.
 5. The method of claim 4, wherein in (a), the at least one row of segments includes an innermost row of first segments, an outermost row of second segments and an intermediate row of third segments; wherein the first segments are aligned with the second segments, and the third segments are misaligned with the first segments.
 6. The method of claim 1, wherein in (a), the substrate structure further comprises an upper solder resist layer covering the upper reinforcing structure.
 7. The method of claim 1, wherein in (a), the substrate structure further comprises a lower side rail opposite to the upper side rail, wherein the lower side rail includes: a lower stress relief structure corresponding to the upper stress relief structure; and a lower reinforcing structure surrounding the lower stress relief structure, wherein a stress relieving ability of the lower stress relief structure is greater than a stress relieving ability of the lower reinforcing structure, and a structural strength of the lower reinforcing structure is greater than a structural strength of the lower stress relief structure.
 8. The method of claim 7, wherein in (a), the substrate structure further comprises: a main body having an upper surface and a lower surface opposite to the upper surface; an upper metal layer disposed adjacent to the upper surface of the main body, and includes an upper circuit layer, the upper stress relief structure and the upper reinforcing structure, the upper circuit layer is disposed in the chip attach area; wherein an upper residual metal ratio is defined as a ratio of an area of the upper metal layer to an area of the entire upper surface of the main body; and a lower metal layer disposed adjacent to the lower surface of the main body, and includes a lower circuit layer, the lower stress relief structure and the lower reinforcing structure, the lower circuit layer is disposed opposite the upper circuit layer; wherein a lower residual metal ratio is defined as a ratio of an area of the lower metal layer to an area of the entire lower surface of the main body, and a difference between the upper residual metal ratio and the lower residual metal ratio is less than or equal to 4%.
 9. The method of claim 1, wherein in (a), the substrate structure further comprises: a main body having an upper surface and a lower surface opposite to the upper surface; an upper metal layer disposed adjacent to the upper surface of the main body, and includes an upper circuit layer, the upper stress relief structure and the upper reinforcing structure, the upper circuit layer is disposed in the chip attach area; a lower metal layer disposed adjacent to the lower surface of the main body, and includes a lower circuit layer, a lower stress relief structure and a lower reinforcing structure, the lower circuit layer is disposed opposite the upper circuit layer, the lower reinforcing structure surrounds the lower stress relief structure; an upper solder resist layer covering at least a portion of the upper metal layer, wherein an upper solder resist cover ratio is defined as a ratio of an area of the upper solder resist layer to an area of the entire upper surface of the main body; and a lower solder resist layer covering at least a portion of the lower metal layer, wherein a lower solder resist cover ratio is defined as a ratio of an area of the lower solder resist layer to an area of the entire lower surface of the main body, and a difference between the upper solder resist cover ratio and the lower solder resist cover ratio is less than or equal to 5%.
 10. The method of claim 1, wherein in (b), the at least one semiconductor chip is electrically connected to the substrate structure by wire bonding.
 11. The method of claim 1, wherein in (b), the at least one semiconductor chip is electrically connected to the substrate structure by flip-chip bonding.
 12. The method of claim 1, wherein after (c), the method further comprises: (d) conducting a singulation process.
 13. The method of claim 12, wherein in (d), the upper side rail is removed.
 14. The method of claim 1, wherein in (a), a material of the upper stress relief structure is the same as a material of the upper reinforcing structure.
 15. The method of claim 1, wherein in (c), the upper reinforcing structure is spaced apart from the encapsulant through the upper stress relief structure.
 16. A method for manufacturing a semiconductor package, comprising: (a) providing a substrate structure, wherein the substrate structure includes a chip attach area and an upper side rail surrounding the chip attach area, the upper side rail includes an upper stress relief structure and an upper reinforcing structure, the upper stress relief structure surrounds the upper chip attach area, the upper reinforcing structure surrounds the upper stress relief structure, wherein a stress relieving ability of the upper stress relief structure is greater than a stress relieving ability of the upper reinforcing structure, and a structural strength of the upper reinforcing structure is greater than a structural strength of the upper stress relief structure, wherein the upper stress relief structure has at least two stress relief directions, and the stress relief directions are neither perpendicular to nor parallel with an edge of the substrate structure; (b) attaching at least one semiconductor chip to the chip attach area; and (c) forming an encapsulant to cover the at least one semiconductor chip. 